1 Technical Field
The present invention relates to stators for electric rotating machines that are used in, for example, motor vehicles as electric motors and electric generators.
2 Description of Related Art
Conventionally, electric rotating machines, which are used in motor vehicles as electric motors and electric generators, include a rotor and a stator that is disposed in radial opposition to the rotor. The stator includes an annular (or a hollow cylindrical) stator core and a stator coil. The stator core has a plurality of slots arranged in a circumferential direction of the stator core. The stator coil is mounted on the stator core so as to be received in the slots of the stator core. Moreover, to reduce iron loss, the stator core is generally formed by laminating a plurality of steel sheets in the axial direction thereof.
Patent Document 1 (i.e., Japanese Patent Application Publication No. JP2010288424A) discloses an annular stator core which is comprised of a plurality of stator core segments that are arranged in the circumferential direction of the stator core so as to adjoin one another in the circumferential direction. Moreover, also for the purpose of reducing iron loss, each of the stator core segments is formed by laminating a plurality of steel sheets in the axial direction of the stator core.
Patent Document 2 (i.e., Japanese Patent Application Publication No. JP2011097790A) discloses a heating device that includes an induction coil for induction-heating a stator core which has a stator coil mounted thereon.
Specifically, the heating device disclosed in Patent Document 2 is designed to fix the stator coil to the stator core by heating and thereby setting (or hardening) a liquid thermosetting resin (e.g., varnish) with the heat of the stator core that is induction-heated.
More specifically, the liquid thermosetting resin is impregnated into predetermined portions of the stator coil, which are received in the slots of the stator core, and retained at the predetermined portions. Then, the induction coil of the heating device, which is placed at a predetermined position radially inside the annular stator core, is energized to induction-heat the stator core to the setting temperature of the thermosetting resin. Consequently, with increase in the temperature of the stator core, the thermosetting resin is heated and set, thereby fixing the stator coil to the stator core.
However, since the thermosetting resin is initially in the liquid state, it may be difficult to impregnate the thermosetting resin into the predetermined portions of the stator coil and retain the same at the predetermined portions. Consequently, it may be difficult to set the thermosetting resin at the predetermined portions.